Name of Polygon.

No of Sides

Apothem or Perpend'lar.

Area when Side is Unity

Interior Angle.

Central Angle.

Triangle

3

0.2887

0.4330

60° 0'

120° 0'

Square

4

0.5

1.

90. 0

90 0

Pentagon

5

0.6882

1.7205

108 0

72 0

Hexagon

6

0.8660

2.5981

120 0

60 0

Heptagon

7

1.0386

3.6339

128 34f

51 25 3/7

Octagon

8

1.2071

4.8284

135 0

45 0

Nonagon

9

1.3737

6.1818

140 0

40 0

Decagon

10

1.5388

7.6942

144 0

36 0

Undecagon

11

1.7028

9.3656

147 16 4/11

32 43 7/11

Dodecagon

12

1.8660

11.1962

150 0

30 0

The tabular area of the corresponding polygon multiplied by the square of the side of the given polygon equals the area of the given polygon.